How to Fertilize Evergreens
Evergreen trees and shrubs benefit from fertilizer applications and soil amendments that add nitrogen and enrich the nutrient value of the soil. Young evergreens will require fertilizer once or twice per year while healthy mature evergreens will need less fertilizer applied every other year or once per year at the most, if at all. Sub par growth or discolored foliage is a sign in mature evergreens that soil is in need of fertilizing.
Amend the soil around evergreens with organic fertilizer at planting time or top dress the surrounding soil every year or two with several pounds each of well aged manure and quality compost. Create an even layer starting 6-inches out from the trunk to out past the drip line of the evergreen and water in well.
Feed mature established evergreens once each year in the spring with a complete formula granular fertilizer such as a 10-8-6. Apply according to the package label directions but not exceeding 1 pound of fertilizer for every 500 square feet of soil area around the evergreen.
Feed young rapidly growing evergreens with the same 10-8-6 formula in the spring and again in the late summer or fall. Feed young evergreens at a higher rate not to exceed 2 pounds for every 500 square feet of soil area.
Water your evergreens regularly and deeply to supplement annual rainfall. Maintain evenly moist soil when reaching your finger an inch or two down into the soil. Do not let the soil become dry as the evergreen foliage can begin to brown which is irreversible.
Kind Of Fertilizer Is Best For Evergreens?
Evergreens, which keep their leaves or needles throughout the year, often have fertilizer requirements that differ from those of their deciduous cousins, which loose their leaves in fall. In general, the best fertilizer for evergreens has a high nitrogen content. Some evergreens, however, don’t require fertilizer because they receive sufficient nutrients from their environment. Look at the color of their leaves or needles. Consider the plants' growth. Evergreens lacking nutrients may grow more slowly than normal and be shorter than expected. Performing a soil test on the soil around the evergreens will determine whether or not nutrient deficiencies exist. Using a fertilizer that provides the nutrients in which your evergreens are deficient is important. For example, a 10-8-6 fertilizer contains 10 percent nitrogen, 8 percent phosphorus and 6 percent potassium. For a more simple calculation of how much fertilizer to use, apply 1/3 pound of a commercial, high-nitrogen fertilizer such as 20-10-5 or 12-6-4 per 1 foot of tree height or canopy spread. Fill each hole to the top with fertilizer.
- Compost and aged manure
- Granular complete high N fertilizer
- University of Minnesota Extension: Fertilizing Evergreens
- University of Minnesota SULIS: Evergreen Trees and Shrubs
- University of Minnesota Extension: Fertilizing Evergreens (Conifers)
- North Carolina Cooperative Extension: A Gardener’s Guide to Fertilizing Trees and Shrubs
- University of Wisconsin Extension: Evergreens Planting and Care
- Virginia Cooperative Extension: Fertilizing Landscape Trees and Shrubs
- University of New Hampshire Cooperative Extension: Fertilizing Trees and Shrubs